package org.imyy.js;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
 * Servlet implementation class Validate
 */
@WebServlet("/Validate")
public class Validate extends HttpServlet {
	public static final char[] CHARS = {'1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','J','K','M','N','P','Q','R','S','T','U','W','X','Y','Z'};
	public static Random random = new Random();
	
	/*
	 * 获取随机数
	 */
	public static String getRandomString(){
		StringBuffer buffer = new StringBuffer();
		for (int i = 0; i < 4; i++) {
			buffer.append(CHARS[random.nextInt(CHARS.length)]);
		}
		return buffer.toString();
	}
	/*
	 * 获取随即颜色
	 */
	public static Color getRandomColor(){
		return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
	}
	/*
	 * 获取反色值
	 */
	public static Color getReverseColor(Color c){
		return new Color(255 - c.getRed(),255 - c.getGreen(),255 - c.getBlue());
	}
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Validate() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("image/jpeg");
		String randomString = getRandomString();
		response.setHeader("woshigyl", randomString);
		request.getSession(true).setAttribute("randomString",randomString);
		int width = 62;
		int height = 24;
		Color color = getRandomColor();
		Color reverseColor = getReverseColor(color);
		BufferedImage bi =  new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics2D g = bi.createGraphics();
		g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
		g.setColor(color);
		g.fillRect(0, 0, width, height);
		g.setColor(reverseColor);
		g.drawString(randomString, 10, 20);
		for (int i = 0, n= random.nextInt(35);i <n; i++) {
			g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
		}
		ServletOutputStream out = response.getOutputStream();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		encoder.encode(bi);
		out.flush();
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
	}

}
